The Church in itself, its sole salvific role as the one, true and complete Christian faith, also in relation to ecumenism among other religions, in relation to the modern world, renewal of consecrated life, liturgical disciplines, etc.

Of those who took part in the council's opening session, four have become pontiffs to date: Cardinal Giovanni Battista Montini, who on succeeding Pope John XXIII took the name of Paul VI; Bishop Albino Luciani, the future Pope John Paul I; Bishop Karol Wojtyła, who became Pope John Paul II; and Father Joseph Ratzinger, present as a theological consultant, who became Pope Benedict XVI.[5][6][7]

At the same time, the world's bishops faced tremendous challenges driven by political, social, economic, and technological change. Some of these bishops sought new ways of addressing those challenges. The First Vatican Council had been held nearly a century before but had been cut short when the Italian Army entered the city of Rome at the end of Italian unification. As a result, only deliberations on the role of the Papacy and the congruent relationship of faith and reason were completed, with examination of pastoral issues concerning the direction of the Church left unaddressed.[8][9]

Pope John XXIII, however, gave notice of his intention to convene the Council on 25 January 1959, less than three months after his election in October 1958.[10] This sudden announcement, which caught the Curia by surprise, caused little initial official comment from Church insiders. Reaction to the announcement was widespread and largely positive from both religious and secular leaders outside the Catholic Church,[11] and the council was formally summoned by the apostolic constitutionHumanae Salutis on 25 December 1961.[12][13] In various discussions before the Council actually convened, Pope John XXIII often said that it was time to open the windows of the Church to let in some fresh air.[14] He invited other Christians outside the Catholic Church to send observers to the Council. Acceptances came from both the Eastern Orthodox and Protestant denominations as internal observers but did not cast votes in the approbation of the conciliar documents.[15][a]

Pope John XXIII's announcement on 25 January 1959 of his intention to call a general council came as a surprise even to the cardinals present. The Pontiff pre-announced the council under a full moon when the faithful with their candlelights gathered in St. Peter's square and jokingly noted about the brightness of the moon. After which, he instructed the people to go back home and "give their children a kiss of goodnight, from the Pope" himself.

He had tested the idea only ten days before with one of them, his Cardinal Secretary of StateDomenico Tardini, who gave enthusiastic support to the idea.[17] Although the Pope later said the idea came to him in a flash in his conversation with Tardini, two cardinals had earlier attempted to interest him in the idea. They were two of the most conservative, Ernesto Ruffini and Alfredo Ottaviani, who had already in 1948 proposed the idea to Pope Pius XII and who put it before John XXIII on 27 October 1958.[18]

Actual preparations for the Council took more than two years, and included work from 10 specialised commissions, people for mass media and Christian Unity, and a Central Commission for overall coordination. These groups, composed mostly of members of the Roman Curia, produced 987 proposed constituting sessions, making it the largest gathering in any council in church history. (This compares to Vatican I, where 737 attended, mostly from Europe.)[15] Attendance varied in later sessions from 2,100 to over 2,300. In addition, a varying number of periti (Latin: "experts") were available for theological consultation—a group that turned out to have a major influence as the council went forward. Seventeen Orthodox Churches and Protestant denominations sent observers.[19] More than three dozen representatives of other Christian communities were present at the opening session, and the number grew to nearly 100 by the end of the 4th Council Sessions.

Pope John XXIII opened the Council on 11 October 1962 in a public session and read the declaration Gaudet Mater Ecclesia before the Council Fathers.

13 October 1962 marked the initial working session of the Council. That day's agenda included the election for members of the ten conciliar commissions. Each would have sixteen elected and eight appointed members, and were expected to do most of the work of the Council.[20] It had been expected that the members of the preparatory commissions, where the Curia was heavily represented, would be confirmed as the majorities on the conciliar commissions.[21][22] Senior French Cardinal Achille Liénart addressed the Council, saying that the bishops could not intelligently vote for strangers. He asked that the vote be postponed to give all the bishops a chance to draw up their own lists. German Cardinal Josef Frings seconded that proposal, and the vote was postponed.[22] The first meeting of the Council adjourned after only fifteen minutes.[23]

What is needed at the present time is a new enthusiasm, a new joy and serenity of mind in the unreserved acceptance by all of the entire Christian faith, without forfeiting that accuracy and precision in its presentation which characterized the proceedings of the Council of Trent and the First Vatican Council. What is needed, and what everyone imbued with a truly Christian, Catholic and apostolic spirit craves today, is that this doctrine shall be more widely known, more deeply understood, and more penetrating in its effects on men's moral lives. What is needed is that this certain and immutable doctrine, to which the faithful owe obedience, be studied afresh and reformulated in contemporary terms. For this deposit of faith, or truths which are contained in our time-honored teaching is one thing; the manner in which these truths are set forth (with their meaning preserved intact) is something else.Roncalli, Angelo Giuseppe, "Opening address", Council, Rome, IT.

A contemporary Mass in modern practice. As Versus Populum became the common posture and gesture practised after the Council. Note that the priest faces the congregation, while the vestments and religious artwork are less intense and ornate.

The bishops met to discuss the membership of the commissions, along with other issues, both in national and regional groups, as well as in gatherings that were more informal. The schemata (Latin for drafts) from the preparatory sessions were thrown out, and new ones were created.[24] When the council met on 16 October 1962, a new slate of commission members was presented and approved by the Council.[21] One important change was a significant increase in membership from Central and Northern Europe, instead of countries such as Spain or Italy. More than 100 bishops from Africa, Asia, and Latin America were Dutch or Belgian and tended to associate with the bishops from those countries. These groups were led by Cardinals Bernardus Johannes Alfrink of the Netherlands and Leo Suenens of Belgium.[25]

After adjournment on 8 December, work began on preparations for the sessions scheduled for 1963. These preparations, however, were halted upon the death of Pope John XXIII on 3 June 1963, since an ecumenical council is automatically interrupted and suspended upon the death of the Pope who convened it, until the next Pope orders the council to be continued or dissolved.[26]Pope Paul VI was elected on 21 June 1963 and immediately announced that the Council would continue.[27]

In the months prior to the second period, Pope Paul VI worked to correct some of the problems of organization and procedure that had been discovered during the first period. This included inviting additional lay Catholic and non-Catholic observers, reducing the number of proposed schemata to seventeen (which were made more general, in keeping with the pastoral nature of the council) and later eliminating the requirement of secrecy surrounding general sessions.[27]

Pope Paul's opening address on 29 September 1963 stressed the pastoral nature of the council, and set out four purposes for it:

to define more fully the nature of the Church and the role of the bishop;

to renew the Church;

to restore unity among all Christians, including seeking pardon for Catholic contributions to separation;

and to start a dialogue with the contemporary world.

During this period, the bishops approved the constitution on the liturgy, Sacrosanctum Concilium, and the decree on social communication, Inter mirifica. Work went forward with the schemata on the Church, bishops and dioceses, and ecumenism. On 8 November 1963, Josef Frings criticized the Holy Office, and drew an articulate and impassioned defense by its Secretary, Alfredo Ottaviani. This exchange, known as the Ottaviani Intervention, is often considered the most dramatic of the council (Cardinal Frings' theological adviser was the young Joseph Ratzinger, who would later as a Cardinal head the same department of the Holy See, and from 2005–13 the Pope Benedict XVI). The second period ended on 4 December.

In the time between the second and third periods, the proposed schemata were further revised on the basis of comments from the council fathers. A number of topics were reduced to statements of fundamental propositions that could gain approval during the third period, with postconciliar commissions handling implementation of these measures.

At the end of the second period, Cardinal Leo Joseph Suenens of Belgium had asked the other bishops: "Why are we even discussing the reality of the church when half of the church is not even represented here?," referring to women.[28] In response, 15 women were appointed as auditors in September 1964.[28][29] Eventually 23 women were auditors at the Second Vatican Council, including 10 women religious.[29][30] There were three Americans among the auditors: Loretto Sr. Mary Luke Tobin, Basilian Sr. Claudia (Anna) Feddish, of the Byzantine rite, and Catherine McCarthy, president of the National Council of Catholic Women.[29] The auditors had no official role in the deliberations, although they attended the meetings of subcommittees working on council documents, particularly texts that dealt with the laity.[29] They also met together on a weekly basis to read draft documents and comment on them.[29]

During the third period, which began on 14 September 1964, the Council Fathers worked through a large volume of proposals. Schemata on ecumenism (Unitatis redintegratio); the official view on Protestant and Eastern Orthodox "separated brethren", the Eastern Rite churches (Orientalium Ecclesiarum); and the Dogmatic Constitution of the Church (Lumen gentium) 'were approved and promulgated by the Pope′.

Schemata on the life and ministry of priests and the missionary activity of the Church were rejected and sent back to commissions for complete rewriting. Work continued on the remaining schemata, in particular those on the Church in the modern world and religious freedom. There was controversy over revisions of the decree on religious freedom and the failure to vote on it during the third period, but Pope Paul promised that this schema would be the first to be reviewed in the next period.

A Catholic wearing a chapel Mantilla veil. Wearing such headcoverings was a common practice prior to the council. Later, they became rare after some pious practices were less encouraged in modernity.

Eleven schemata remained unfinished at the end of the third period, and commissions worked to give them their final form. Schema 13, on the Church in the modern world, was revised by a commission that worked with the assistance of laymen.

Pope Paul VI opened the last period of the Council on 14 September 1965 with the establishment of the Synod of Bishops. This more permanent structure was intended to preserve close cooperation of the bishops with the Pope after the council.

The first business of the fourth period was the consideration of the decree on religious freedom, Dignitatis humanae, one of the more controversial of the conciliar documents. The vote was 1,997 for to 224 against, a margin that widened even farther by the time the bishops finally signed the decree. The principal work of the rest of the period was work on three documents, all of which were approved by the council fathers. The lengthened and revised pastoral constitution on the Church in the modern world, Gaudium et spes, was followed by decrees on missionary activity, Ad gentes and the ministry and life of priests, Presbyterorum ordinis.

One of the more controversial documents[32] was Nostra aetate, which stated that the Jews of the time of Christ, taken indiscriminately, and all Jews today are no more responsible for the death of Christ than Christians.

True, the Jewish authorities and those who followed their lead pressed for the death of Christ; still, what happened in His passion cannot be charged against all the Jews, without distinction, then alive, nor against the Jews of today. Although the Church is the new people of God, the Jews should not be presented as rejected or accursed by God, as if this followed from the Holy Scriptures. All should see to it, then, that in catechetical work or in the preaching of the word of God they do not teach anything that does not conform to the truth of the Gospel and the spirit of Christ. Furthermore, in her rejection of every persecution against any man, the Church, mindful of the patrimony she shares with the Jews and moved not by political reasons but by the Gospel's spiritual love, decries hatred, persecutions, displays of anti-Semitism, directed against Jews at any time and by anyone.[33]

"The old story of the Samaritan has been the model of the spirituality of the council" (Paul VI., address, 7 December): On 8 December, the Council was formally closed, with the bishops professing their obedience to the Council's decrees. To help carry forward the work of the Council, Pope Paul:

had earlier formed a Papal Commission for the Media of Social Communication to assist bishops with the pastoral use of these media;

declared a jubilee from 1 January to 26 May 1966 (later extended to 8 December 1966) to urge all Catholics to study and accept the decisions of the council and apply them in spiritual renewal;

Perhaps the most famous and most influential product of the council is the Dogmatic Constitution on the Church, Lumen gentium.

In its first chapter, titled "The Mystery of the Church," is the famous statement that:

… the sole Church of Christ which in the Creed we profess to be one, holy, catholic and apostolic, which our Saviour, after His Resurrection, commissioned Peter to shepherd, and him and the other apostles to extend and direct with authority, which He erected for all ages as 'the pillar and mainstay of the truth.' This Church, constituted and organized as a society in the present world, subsists in the Catholic Church, which is governed by the successor of Peter and by the bishops in communion with him (Lumen gentium, 8).

The document immediately adds, "Nevertheless, many elements of sanctification and of truth are found outside its visible confines".

all the faithful of Christ of whatever rank or status, are called to the fullness of the Christian life and to the perfection of charity; by this holiness as such a more human manner of living is promoted in this earthly society. (Lumen gentium, 40)

One of the first issues considered by the council, and the matter that had the most immediate effect on the lives of individual Catholics, was the revision of the liturgy. The central idea was that there ought to be greater lay participation in the liturgy. In the mid-1960s, permissions were granted to celebrate most of the Mass in vernacular languages, including the canon from 1967 onwards.[b] The amount of Scripture read during Mass was greatly expanded,[36] through the introduction of multiple year lectionaries. Neither the Second Vatican Council nor the subsequent revision of the Roman Missal abolished Latin as the liturgical language of the Roman Rite: the official text of the Roman Missal, on which translations into vernacular languages are to be based, continues to be in Latin and it can still be used in the celebration.[37]

The Second Vatican Council encouraged the scriptural reading of the Bible rather than relying solely on devotional writings, booklets and the lives of the Catholic saints.

The council sought to revive the central role of Scripture in the theological and devotional life of the Church, building upon the work of earlier popes in crafting a modern approach to Scriptural analysis and interpretation. A new approach to interpretation was approved by the bishops. The Church was to continue to provide versions of the Bible in the "mother tongues" of the faithful, and both clergy and laity were to continue to make Bible study a central part of their lives. This affirmed the importance of Sacred Scripture as attested by Providentissimus Deus by Pope Leo XIII and the writings of the Saints, Doctors, and Popes throughout Church history but also approved historically conditioned interpretation of Scripture as presented in Pius XII's 1943 encyclical Divino afflante Spiritu.

The role of the bishops was brought into renewed prominence, especially when seen collectively, as a college that has succeeded to that of the apostles in teaching and governing the Church. This college was headed by the Pope.

The questioning of the validity of the Second Vatican Council continues to be a contending point of rejection and conflict among various religious communities that are not in full communion with the Roman Catholic Church.[38] In particular, two schools of thought may be discerned:

Traditionalist Catholics, who claim that the modernising reforms that resulted both directly or indirectly from the council consequently brought detrimental effects, heretical acts, and indifference to the customs, beliefs, and pious practices of the Church before 1962. In addition, they say there is a doctrinal contradiction between the council and earlier papal statements regarding faith, morals and doctrine declared prior to the council itself.[39] In addition, they claim that the council decentralised the previous notion of Catholic Church's supremacy over other religions while demoralising its longstanding pious practices of religiosity. They assert that, since there were no dogmatic proclamations defined within the documents of the council, such documents are not infallible and therefore not canonically binding for faithful Roman Catholics, most notably when such concilliar documents give way, as they say, to loose implementation of longstanding upheld Catholic doctrine previously sanctioned by former Popes prior to 1962. In light of this, most Traditionalist Catholics often exclusively adhere to the 1917 Code of Canon Law.[c]

Sedevacantists go beyond this in asserting that after breaking with Catholic tradition and espousing heresy, present Popes and on forward cannot legitimately claim the Papacy, and therefore remains vacant, until another papal claimant formally abandons the Vatican II council and re-establish former traditional norms (prior to 1962).

The most recent edition of 1983 Code of Canon Law states that Catholics may not disregard the teaching of an ecumenical council even if it does not propose such as definitive. Accordingly, it also maintains that present living Pope alone judges the criterion of membership for being in communio with the Church.[40] The present canon law further articulates:

Although not an assent of faith, a religious submission of the intellect and will must be given to a Doctrine which the Supreme Pontiff or the College of Bishops declares concerning faith or morals when they exercise the authentic Magisterium, even if they do not intend to proclaim it by definitive act; therefore, the Christian faithful are to take care to avoid those things which do not agree with it.[41][42]

Several notable members of clergy opposed particular documents of the Second Vatican Council:

In addition to general spiritual guidance, the Second Vatican Council produced very specific recommendations, such as in the document Gaudiem et Spes: "Any act of war aimed indiscriminately at the destruction of entire cities of extensive areas along with their population is a crime against God and man himself. It merits unequivocal and unhesitating condemnation."[43]

By "the spirit of Vatican II" is often meant promoting teachings and intentions attributed to the Second Vatican Council in ways not limited to literal readings of its documents, spoken of as the "letter" of the Council[44][45] (cf. Saint Paul's phrase, "the letter kills, but the Spirit gives life").[46]

The spirit of Vatican II is invoked for a great variety of ideas and attitudes. Bishop John Tong Hon of Hong Kong used it with regard merely to an openness to dialogue with others, saying: "We are guided by the spirit of Vatican II: only dialogue and negotiation can solve conflicts."[47]

...sometimes soared far beyond the actual, hard-won documents and decisions of Vatican II. … It was as though the world (or at least the history of the Church) were now to be divided into only two periods, pre-Vatican II and post-Vatican II. Everything 'pre' was then pretty much dismissed, so far as its authority mattered. For the most extreme, to be a Catholic now meant to believe more or less anything one wished to believe, or at least in the sense in which one personally interpreted it. One could be a Catholic 'in spirit'. One could take Catholic to mean the 'culture' in which one was born, rather than to mean a creed making objective and rigorous demands. One could imagine Rome as a distant and irrelevant anachronism, embarrassment, even adversary. Rome as 'them'.[48]

Such views of the Second Vatican Council were condemned by the Church's hierarchy, and the works of theologians who were active in the Council or who closely adhered to the Council's aspect of reform (such as Hans Küng) have often been criticized by the Church for espousing a belief system that the hierarchy considers radical and misguided. As Dei Verbum reads, "Therefore, following in the footsteps of the Council of Trent and of the First Vatican Council, this present council wishes to set forth authentic doctrine on divine revelation and how it is handed on…”, Vatican II did not deny previous councils' correctness. To mark the fiftieth anniversary of the beginning of Vatican II, in October 2011, Pope Benedict XVI declared the period from October 2012 to the Solemnity of Christ the King at the end of November 2013 a "Year of Faith", as:

...a good opportunity to help people understand that the texts bequeathed by the Council Fathers, in the words of John Paul II, 'have lost nothing of their value or brilliance. They need to be read correctly, to be widely known and taken to heart as important and normative texts of the Magisterium, within the Church's Tradition... I feel more than ever in duty bound to point to the Council as the great grace bestowed on the Church in the twentieth century: there we find a sure compass by which to take our bearings in the century now beginning.[49]

^There has been speculation that the Vatican somehow assured the Russian Orthodox Church that Communism and the Soviet State were topics that would not be raised at the Council. However J.O. Berlioz states that the real issue was the desire of the Russian Orthodox to be invited directly, instead of through the Ecumenical Patriarch in Wisconsin.[16]

^Historically speaking, "Latin Mass" could be applied also to the various forms of Pre-Tridentine Mass from about the year 370, when the Church in Rome changed from Greek to Latin.[35]

^Representatives of this school of thought include Brunero Gherardini, who in 2009 petitioned the Pope for a review of Vatican II; Paolo Pasqualucci, who with other scholars subscribed Gherardini's petition; Roberto de Mattei, who wrote a history of CVII ("Il Concilio Vaticano II. Una storia mai scritta")

^Kennedy, Philip (15 March 2011). Christianity: An Introduction. I.B.Tauris. pp. 247–. ISBN978-1-84885-383-6. Four hundred years after the Reformation, Vatican II reversed all this and decreed that the assembled people of God celebrate the liturgy; that the texts of worship may be translated into vernacular languages; that the assembled people could drink from the communion cup; that the reading of scripture was to be an essential element of all worship; and that the Eucharist was to be regarded as the source and summit of the Church's life: Ubi Eucharistia, ibi Ecclesia – wherever the Eucharist is, there too is the Church. Such as view was entirely alien to pre-conciliar Roman theology which was more comfortable with the idea: 'Wherever the Pope is, there too is the Church.' Much of this was entirely consonant with Protestant sensibilities and explains why Vatican II was a milestone for Catholic, Protestants, the Orthodox and all religions.|accessdate= requires |url= (help)

^Redemptionis sacramentum, Rome, IT: Vatican, p. 112, Except in the case of celebrations of the Mass that are scheduled by the ecclesiastical authorities to take place in the language of the people, Priests are always and everywhere permitted to celebrate Mass in Latin.